I think sometimes people expect me to be really nitpicky about the science in fiction, like sit there watching the Planet Killer in Star Wars going ‘pfft… that would never happen’.  And yes it is a complete nonsense, but generally no I don’t really nitpick these things.  Star Wars is obviously fantasy anyway.  Maybe it’s different if something actually markets itself as being amazingly scientifically accurate, but in general things only bother me if a sci-fi/fantasy tale is inconsistent with it’s own rules.  If the story establishes that a spaceship’s top speed is 10x the speed of light, you have to stick with that from now on.  You can’t just suddenly make it faster because your characters need to get somewhere in a hurry – you’ll just have to find another way or come up with an explanation as to how they can give the engine more oomph.